1. Field of the Invention
This invention relates generally to magnetomechanical tags used in electronic article surveillance (EAS) systems, and more particularly, to methods for manufacturing EAS tags.
2. Description of the Related Art
In acoustomagnetic or magnetomechanical electronic article surveillance, or “EAS,” a detection system may excite an EAS tag by transmitting an electromagnetic burst at a resonance frequency of the tag. When the tag is present within an interrogation zone defined by the electromagnetic field generated by the burst transmitter, the tag resonates with an acoustomagnetic or magnetomechanical response frequency that is detectable by a receiver in the detection system.
EAS systems may be provided to prevent or deter theft of merchandise from retail establishments. In a typical EAS system, EAS tags configured to interact with an electromagnetic or magnetic field generated by equipment placed, for example, at an exit of a store are utilized. Removable EAS tags that may be configured as labels are typically placed on the article at the store or at an intermediate location. Alternatively, EAS tags or labels may be integrated into the article during manufacture in a process known as “source tagging.”
If an EAS tag is brought into the field or interrogation zone of the field generating equipment, the presence of the tag is detected and an alarm may be generated, such as a visual or audible alarm. Removable EAS tags are typically removed at the checkout counter upon payment for the merchandise. Other types of EAS tags, such as EAS tags integrated with the article, are deactivated at the checkout counter, for example, by a deactivation device that changes an electromagnetic or magnetic characteristic of the EAS tag such that the presence of the EAS tag will no longer be detected within the interrogation zone.
EAS tags are typically assembled in a stacking or layering process wherein the various component parts are attached and sealed together. During the assembly process, a powder lubricant is applied to reduce the friction between some of the component parts (e.g., between a resonator and substrate). The applied powder lubricant is typically not applied in a controlled process and may affect the heat sealing of the EAS tag, for example, not allow proper or complete sealing of the EAS tag because too much powder lubricant is applied. Also, because the applied powder lubricant process is not controlled, too little powder lubricant may be applied resulting in increased friction within the EAS tag and a potential reduction of tag signal amplitude. Thus, the addition of too little or too much powder lubricant affects the assembly and operation of the EAS tags.